"Public health concerns over declining sleep duration do not appear to be warranted."

Image: alvarez/iStockphoto

University of Sydney researchers have debunked the widespread belief that technological devices such as computers and mobile phones are increasingly eating into our sleep.

In a paper just published in the December issue of the Medical Journal of Australia, Nicholas Glozier, Associate Professor of Psychological Medicine, and co-authors apply some scientific rigour to the common perception that Australians were sleeping an hour less than they did a decade ago.

Using Australian Bureau of Statistics data from 1992, 1997 and 2006, they found the average adult slept 8 hours and 20 minutes in 1992, 8 hours and 33 minutes in 1997 and 8 hours and 30 minutes in 2006.

After adjusting the figures to take into account weekends and different seasons, the authors found there was no significant change in average sleep duration between 1992 and 2006.

The exceptions were people aged 65 and over, who on average slept 12 minutes less than they did in 1992. People with no income slept 17 minutes less and male carers slept 31 minutes less than they did in 1992 - though all still averaged more than 8 hours.

The authors also found that:

shorter sleep duration was associated with higher education, higher income, longer work hours and having two or more children in the household;

adults average 40 minutes more sleep per night on weekends;

adults sleep 12 minutes longer per night in winter than they do in summer.

The overall findings were positive, given that sleep deprivation is associated with a number of health problems, including premature death, heart health, obesity, accident and injury, and mental health problems.

"Public health concerns over declining sleep duration do not appear to be warranted", the authors wrote. "The time allocated to sleep by Australian adults appears to have withstood the challenges of societal and technological change during this period."